ftrace: return error on failed modified text.

Have the ftrace_modify_code return error values:

  -EFAULT on error of reading the address

  -EINVAL if what is read does not match what it expected

  -EPERM  if the write fails to update after a successful match.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 7 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8821ceabf51d..428291581cb2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -62,7 +62,6 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
                    unsigned char *new_code)
 {
         unsigned char replaced[MCOUNT_INSN_SIZE];
-        int ret;
 
         /*
          * Note: Due to modules and __init, code can
@@ -72,15 +71,16 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
          * No real locking needed, this code is run through
          * kstop_machine, or before SMP starts.
          */
-        if (__copy_from_user_inatomic(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
-                return 1;
+        if (__copy_from_user_inatomic(replaced, (char __user *)ip,
+                                      MCOUNT_INSN_SIZE))
+                return -EFAULT;
 
         if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
-                return 2;
+                return -EINVAL;
 
-        ret = __copy_to_user_inatomic((char __user *)ip, new_code,
-                                        MCOUNT_INSN_SIZE);
-        WARN_ON_ONCE(ret);
+        if (__copy_to_user_inatomic((char __user *)ip, new_code,
+                                    MCOUNT_INSN_SIZE))
+                return -EPERM;
 
         sync_core();